<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #app {
            width: 800px;
            height: 200px;

        }

        ul {
            overflow: hidden;
        }

        li {
            float: left;
            margin: 20px;
            list-style: none;
            width: 30px;
            height: 30px;
            background-color: red;
            text-align: center;
            line-height: 30px;
        }
    </style>
</head>

<body>

    <div id="app">
        <button>自动生成10个li</button>
        <ul></ul>
    </div>

</body>
<script src="../js/task3.js"></script>

</html>